The present invention relates to semiconductor memory devices, and more specifically, a magnetic memory device including a magnetoresistive random access memory (MRAM), and a manufacturing method thereof.
The MRAM is a device for storing information by magnetism. The MRAM has advantages in high-speed operation, resistance to rewriting, nonvolatility, and the like, as compared to other memory techniques. The typical MRAM includes bit lines and word lines serving as writing conductors, and a memory cell of a magnetoresistive element.
The layout of write conductors in the conventional MRAM is disclosed in, for example, Japanese Unexamined Patent Publication No. 2002-18239 (Patent Document 1). The layout of the write conductors disclosed in Patent Document 1 includes a first conductor having a first width, a second conductor having a second width, and a data storage layer. The first conductor and the second conductor are perpendicular to each other, and the data storage layer is positioned above the first conductor and below the second conductor at the intersection of the first conductor and the second conductor. The data storage layer has a first layer width and a second layer width. The first width of the first conductor is smaller than the first layer width of the data storage layer, and the second width of the second conductor is smaller than the second layer width of the data storage layer. In writing data in the data storage layer, current is allowed to flow through the first and second conductors, which generates a magnetic field to change the direction of magnetization of the data storage layer.